Physics test 3An object that has kinetic energy must be

A 2500-N pile-driver ram falls 10 m and drives a post 0.1 m into the ground. The average impact force on the ram is

250,000 N

one kilowatt-hour represents

3.6 million joules

Room temperature on the Kelvin scale is about

300 K

The amount of heat needed to raise the temperature of 1 gram of water by 1°C is

4.19 Joules

The work done in pushing a TV set a distance of 2 m with an average force of 20 N is

40 J

When 10 grams of hot water cool by 1°C, the amount of heat given off is

41.9 Joules

A toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed using 1000 J of work, is

50 W

A jack system will increase the potential energy of a heavy load by 1000 J with a work input of 2000 J. The efficiency of the jack system is

50%

Danny Diver weighs 500 N and steps off a diving board 10 m above the water. Danny hits the water with kinetic energy of

5000J

The power required to exert 4-N force over 3 meters in 2 seconds is

6 W

A 2-kg ball is held 4 m above the ground. Relative to the ground its potential energy is

80 J

A motorcycle moving at 50 km/h skids 10 m with locked brakes. How far will it skid with locked brakes when traveling at 150 km/h?

90 m

Which has greater kinetic energy?

a car of half the mass traveling at 60km/hr

The air in your room is composed of molecules that have

a wide variety of speeds

The ram of a pile driver drops onto the top of an iron beam, driving it partway into the ground. The distance that the beam sinks into the ground depends on the

all of the above

Aluminum has a higher specific heat capacity than iron. This means that for equal masses of aluminum and iron, the metal that heats more quickly when the same amount of heat is applied is

iron

Which of the following normally warms up fastest when heat is applied?

iron

The amount of work done on a heavy box carried by Nellie across a room at a constant speed

is none

Temperature is most closely related to molecular

kinetic energy

When a drawn bow of potential energy 40 J is fired, the arrow will ideally have a kinetic energy

of 40 J

If the speed of a bicycle is reduced to half before skidding to a stop, it will skid

one-fourth as far

If the specific heat capacity of water were lower than it is, a watermelon in a picnic cooler would cool in a

shorter time

A bicycle that travels four as fast as another when braking to a stop will skid

sixteen times as far.

When wind encounters a wind turbine that produces energy, wind speed on the downside of the blades is

slowed

Which requires the most amount of work by the brakes of a car?

slowing down from 100 km/h to 70 km/h

The specific heat capacity is highest for substances that absorb or release large quantities of heat for correspondingly

small temperature changes

Heat energy travels from an object with a high

temperature to an object with a lower temperature.

A ball rolling down an incline has its maximum kinetic energy at

the bottom

No work is done by gravity on a bowling ball that rolls along a bowling alley because

the force on the ball is at right angles to the ball's motion

Both a 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time. The power expended in raising the 50-kg sack is

the same

About 40 J is required to push a crate 4 m across a floor. If the push is in the same direction as the motion of the crate, the force on the crate is about

10 N

Two identical particles move toward each other, one twice as fast as the other. Just before they collide, one has a kinetic energy of 25 J and the other 50 J. At this instant their total kinetic energy is

75 J

A car's engine is 20% efficient. When cruising, the car encounters an average retarding force of 1000 N. If the energy content of fuel is 40 megajoules per liter, how many kilometers per liter does the car achieve?

8

which unit represents the most energy

Calorie

Which temperature scale has the smallest sized degrees?

Fahrenheit

A temperature difference of 10 Celsius degrees is also equal to a temperature difference of 10 on the

Kelvin Scale

If the specific heat capacity of water were lower than it is, a nice hot bath would be a

Shorter experience

A cannonball has more kinetic energy than the recoiling cannon from which it is fired because the force on the ball

acts over a longer distance.

A circus diver drops from a high pole into water far below. When he is halfway down

all of the above

The quantity of heat that a substance can transfer relates to its

all of the above

Two identical arrows, one with twice the speed of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

four times as far

The work you do when pushing a shopping cart twice as far while applying twice the force is

four times as much.

Two identical golf carts move at different speeds. The faster cart has twice the speed and therefore has

four times the kinetic energy.

When you touch a hot potato with your finger, energy flows

from the potato to your finger

A clerk can lift cylindrical packages 1 meter vertically, or can roll them up a 2-meter-long ramp to the same elevation. With the ramp, the applied force required is about

half as much

A block of ice sliding down an incline has half its maximum kinetic energy

halfway down

When Joshua brakes his speeding bicycle to a stop, kinetic energy is transformed to

heat

A substance that heats up relatively slowly has a

high specific heat capacity

The moderate temperatures of islands throughout the world has much to do with water's

high specific heat capacity.

Compared to a giant iceberg, a hot cup of coffee has

higher temperature, but less internal energy

A crate of grapes lifted 10 meters gains 200 J of potential energy. If the same crate is instead lifted 20 meters, its gain in potential energy is

twice as much

Relative to an initial height, an object raised twice as high has a gravitational potential energy

twice as much

The work you do when pushing a shopping cart twice as far while applying the same force is

twice as much

A 1000-kg car and a 2000-kg car are hoisted to the same height. Raising the more massive car requires

twice as much work

The work you do when pushing a shopping cart a given distance while applying twice as much force is

twice as much.

A bicycle that travels twice as fast as another when braking to a stop will skid

four times as far

When you touch a cold piece of ice with your finger, energy flows

from your finger to the ice

A 2-kg box of taffy candy has 40 J of potential energy relative to the ground. Its height above the ground is

2 m

A hydraulic press has its input piston depressed 20 centimeters while the output piston is raised 1 centimeter. A 1-newton input can lift a load of

20 N

A hydraulic jack is used to lift objects such as automobiles. If the input force is 200 N over a distance of 1 meter, the output force over a distance of 0.1 meter is ideally

2000N

A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is

10%

A melon is tossed straight upward with 100 J of kinetic energy. If air resistance is negligible the melon will return to its initial level with a kinetic energy of

100 J

Neglecting air resistance, Sammy Smarts on a high ladder releases a ball that strikes the ground with 100 J of kinetic energy. If he were to instead throw the ball straight upward, it will soon reach the ground with a kinetic energy of

100 J

The power expended doing 100 J of work in 50 s is

2 W

Acrobat Bart at the circus drops vertically onto the end of a see-saw, with his partner Art equidistant from the fulcrum at the other end. Art is propelled straight upward a distance twice that of Bart's dropping distance. Neglecting inefficiencies we see

Art has half the mass of Bart

Which temperature scales have equal sized degrees?

Celsius and Kelvin

A moving object has

all of these

Pour a liter of water at 40°C into a liter of water at 20°C and the final temperature of the two becomes

at or about 30 degrees celsius

Heat energy is measured in units of

both of these

Which task requires more work?

both require the same

In which is the temperature greater

both the same

The bob of a simple pendulum has its maximum kinetic energy at the

bottom of its swing

Aluminum has a specific heat capacity more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the one to undergo the fastest increase in temperature will be

copper

Impulse involves the time that a force acts, whereas work involves the

distance that a force acts

The unit kilowatt-hour is a unit of

energy

A roller skate at rest may have

energy.

A melon is projected into the air with 100 J of kinetic energy in the presence of air resistance. When it returns to its initial level its kinetic energy is

less than 100 J

Place a 1-kilogram block of iron at 40°C into 1 kilogram of water at 20°C and the final temperature of the two becomes

less than 30 degrees celsius

The white-hot sparks from a 4th-of-July-type sparkler that strike your skin transfer

little energy to you in spite of their high temperature.

An object has gravitational potential energy due to its

location

One of water's interesting thermal properties is that when heated it takes a relatively

long time in changing temperature

The fact that desert sand is very hot in the day and very cold at night is evidence that the specific heat capacity of sand is relatively

low

A substance that cools down faster than others has a

low specific heat capacity

A substance that heats up relatively quickly has a

low specific heat capacity

A primary difference between momentum and kinetic energy is

momenta can cancel; kinetic energy cannot.

If an all-electric car has kinetic energy, then it also must have

momentum

If the specific heat of water were lower than it is, ponds in the cold winter would be

more likely to freeze

A 1-kg ball dropped from 2 m rebounds only 1.5 m after hitting the ground. The amount of energy converted to heat is about

more than 2.0 J

Pour two liters of water at 40°C into one liter of water at 20°C and the final temperature of the two becomes

more than 30 degrees celsius

If a Ping-Pong ball and a golf ball both move in the same direction with the same amount of kinetic energy, the speed of the Ping-Pong ball must be

more than the golf ball

An object that has kinetic energy must be

moving

A light aluminum ball and a heavy lead ball of the same size roll down an incline. When they are halfway down the incline, they will have identical

none of the above

When you and your snowboard are in motion, which of the following can be zero?

none of the above

After rolling halfway down an incline, a marble's kinetic energy is

the same as its potential energy

Tomatoes have a higher specific heat capacity than dough. This means that when you bite into a hot pizza

the tomato sauce feels hotter than the dough.

A ball rolling down an incline has its maximum potential energy at

the top

The fact that a thermometer "takes its own temperature" illustrates

thermal equilibrium

If you do work on a skateboard loaded with friends in one-third the usual time, you expend

three times the usual power.

Strictly speaking, more fuel is consumed by your car if the air conditioner, headlights, or even a radio is turned on. This statement is

true

Two identical arrows, one with twice the kinetic energy of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

twice as far